"I think the fact that he's moving in on his campaign promises are one of the things — and decent earnings — that are underpinning this," Cashin, the UBS Director of Floor Operations at the NYSE, told "Squawk on the Street" just after the Dow blew past its 20,000 landmark.
"So some credit, yes. All the credit, not quite," he said.
Cashin said markets are encouraged and investors are "somewhat impressed" by Trump instantly taking charge and spearheading some of his campaign promises via executive order. But parts of the president's "America First" policies will be hard to enforce, Cashin said.
"The 'buy American' requirements are going to be a little difficult to put together step by step," he contended.
The biggest contributors to the Dow's 100-point jump were Boeing and Caterpillar. Cashin said he was concerned that market volume, or the number of shares being traded, is a bit too low.
"I really would like to see a little bit more volume because we old-timers believe that volume equals validity," Cashin said. "And [if] you get good volume, that means you're there for real."